Stein Industrie's European patent specification EP-A-0 005 225 describes a steam separator-superheater of this type having a horizontal axis and comprising, above separators for separating out the water entrained by the steam, rectangular bundles of tubes for superheating said steam by exchanging heat with steam at a higher pressure. These bundles are held in frames rigidly connected to beams extending transversely to the axis of the separator-superheater
They do not provide perfect sealing to prevent steam getting round the bundle of tubes by flowing along the sides of the frame. They are capable of being installed in the separator-superheater only on site, e.g. by causing them to run along rails fixed to the bottom portion of the rigid frame.
The object of the present invention is to provide superheat bundles providing excellent sealing against steam getting round the sides of the frame, and also capable of being factory mounted in the separator-superheater.